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1. Field of the Invention
The present invention relates to a tool for threading a lag hook, also known as a j-hook or aj-lag, into the wood of a tree. Still, more particularly, this invention relates such a tool to drive such a lag hook for arboricultural purposes.
2. Description of the Prior Art
In the practice of arboriculture, preventive maintenance and repair measures for woody plants, in particular trees, involve the use of cabling. Threaded fasteners are used to form anchor sites for the installation of a flexible cable between a tree trunk and a tree branch or between tree branches of a tree. Cabling installed between branches functions to limit excessive branch motion and to reduce stress on a crotch formed by the branches and to reduce stress on the branches. The cabling may extend from a tree or a branch thereof to an adjacent tree or to the ground to provide needed support for the branch or trunk of the tree. More commonly, however, the arboriculture procedures will involve connecting two dominant branches of a forked tree so that each of the two dominant branches will support the other branch. Particularly, in the case of forked trees, cabling can effectively prevent or reduce splitting due to wind, ice, or the weight of a dominant branch or fruit produced by these branches.
One fastener commonly used in the cabling of trees is a lag hook. The lag hook has an elongated threaded shank driven into the wood of the tree after drilling a suitable pilot hole. The usual practice of providing a pilot hole involves selecting a drill bit with a diameter about xe2x85x9 inch less than the pitch diameter of the threads on the shank of the lag hook to minimize stress and strain in both the lag hook and the wood of the tree. The threaded shank of the lag hook terminates at a short linear shank having a smooth and slightly larger diameter than the outside diameter of the threads on the shank. Usually, at least part of the short linear shank is advanced into the wood of the tree to gain the benefit of the added strength of the short shank and to seal the entrance to the threads of the threaded shank. The short shank terminates at a reversely curved hook shaped end portion. A considerable mechanical effort is needed to install the lag hook. A lag spinner is a commercially available hand tool used to apply torque to the hook-shaped end of the lag. A wrench or a screwdriver is other known hand tools also used to install a lag hook. Each of the lag spinner, wrench and screwdriver are used as a first class lever by engaging one end of the tool with the reversely curved, hook-shaped end of the lag hook and the free end of the lever receiving the applied torque. The lag hook is unstable under these conditions during the initial threading and at least until the threaded shank is firmly engaged with the wood surrounding the drilled pilot hole. These hand tools are often difficult to manipulate while maintaining the required coaxial relation between the longitudinal axis of the pilot hole and the rotational axis of the lag hook, particularly over the extended period of time needed to install the lag hook. The difficulty is increased because the installer may be suspended in a safety harness attached to one or more safety ropes.
It is an object of the present invention to provide a tool for stabilizing a lag hook during installation in the wood of a tree for arboriculture purposes.
It is another object of the present invention to provide a tool embodying a construction for efficiently transferring torque to the reversely curved hook-shaped end of the lag hook to facilitate driving the lag hook into a trunk or branch of a tree for cabling procedures.
According to the present invention, there is provided a tool for applying torque to the hook formation of a lag hook, the tool comprising an elongated body defining a rotational axis extending along the elongated length thereof between a torque receiving end and an opposite terminal end, an upper portion of the elongated body having upper and lower wall surfaces extending transversely in a spaced apart relation to form a passageway for a curved end portion of a lag hook to a socket traversed by the rotational axis and bounded by a torque delivering wall spaced from the rotational axis, and a shank guide throat extending from the socket by U-shaped surfaces spaced from the rotational axis and extending parallel to the elongated length of the elongated body section between the lower wall surface and the terminal end of the elongated body.
A preferred embodiment of the present invention provides that the upper portion of the elongated body traversed by the spaced apart upper and lower wall surfaces form two passageways at opposite sides of the rotational axis for passage of a curved end portion of a lag hook having left-hand or right-hand threads to the socket traversed by the rotational axis and bounded by a torque delivering wall spaced from the rotational axis.
The present invention further provides a method for cabling a tree including the steps of providing a tool comprising an elongated body defining a rotational axis extending along the elongated length thereof between a torque receiving end and an opposite terminal end, an upper portion of the elongated body having upper and lower wall surfaces extending transversely in a spaced apart relation to form a passageway for a curved end portion of a lag hook to a socket traversed by the rotational axis and bounded by a torque delivering wall spaced from the rotational axis, and a shank guide throat extending from the socket by U-shaped surfaces spaced from the rotational axis and extending parallel to the elongated length of the elongated body between the lower wall surface and the terminal end of the elongated body, passing a reversely curved hook shaped end of a lag hook through the space between the upper and lower surfaces and into contact with the torque delivering wall, positioning a threaded shank of the lag hook along the shank guide throat to align the longitudinal axis of the shank with the rotational axis of the elongated body, positioning the terminal end of the threaded shank against the wood of a tree at a selected site for cabling, rotating the tool about the rotational axis to mount the lag hook on the tree, removing the tool from both the shank and the reversely curved hook-shaped end of the lag hook, affixing one end of a cable to the reversely curved hook-shaped end of the lag hook and affixing the other end of the cable to a remote anchor.